Compact motorized scaffold arrangement



March 19, 1968' G. F. SCHAFER COMPACT MOTORIZED SCAFFOLD ARRANGEMENTFiled May 16, 1966 INVENTOR.

"Gm/m5 E SdHAFER United States Patent 3,373,844 COMPACT MOTORIZEDSCAFFOLD ARRANGEMENT George F. Schafer, El Tahoe, Calif. (R0. BoxAV-Bijou, Lake Tahoe, Calif.) Filed May 16,- 1966, Ser. No. 550,275 1Claim. (Cl. 182-141) ABSTRACT OF THE DISCLOSURE This invention relatesto a lazy tong scaffolding assembly having spaced lazy tong sideportions with transversely extending tie rods for stabilizing theassemblies together with an additional lazy tong assembly mounted uponthe spacing tie rods and operating in a plane perpendicular to thespaced lazy tong assemblies as a stabilizing means and a cableretracting means in the form of a bobbin over which the lazy tongextending cable is wound with superimposed concentric turns to provide amaximum torque during the initial lazy tong extending operation.

My present invention relates to a scaffold forming device and moreparticularly to a mechanized self-contained scaffolding assembly of lazytong construction.

An object of the invention is to provide a novel and practical scaffoldforming device of novel and collapsible construction employing lazy tongassemblies which may be moved about and used adjacent a structurewithout requiring any stabilizing attachment with the structure.

Another object of the invention is to provide a scaffolding arrangementemploying a lazy tong assembly having means by which the assembly isextended and retained by forces applied at several points through cableconnections in a novel, practical and efiicient manner.

A further object of the invention is to provide a scaffolding employingspaced lazy tong assemblies mounted upon a supporting platform havingcable retrieving drums for each of said lazy tong assemblies and a cableinterlaced and extending about pulleys at the ends of each of thepivotally mounted bars of said lazy tong assembly and attached at itsouter end to one of the uppermost of the lazy tong forming bars, wherebysaid cable will operate to apply an extending force for each pair of thecross bars of the lazy tong assembly.

Another object of the invention is to provide a lazy tong scaffoldforming arrangement having parallel lazy tong forming bars connected attheir crossed points by a transversely extending cylindrical shaft withadditional lazy tong assembly extending at a right angle to the planesof said parallel lazy tong bars having crossed links secured along oneside upon said transversely extending shafts and the other sides thereofbeing connected to a slidably mounted collar upon said spaced shafts,whereby said spaced parallel lazy tong assemblies will be held instabilized vertically spaced relationship when extended.

Other objects and advantages will be in part evident to those skilled inthe art and in part pointed out hereinafter in the following descriptiontaken in connection with the accompanying drawing, wherein there isshown by way of illustration and not of limitation a preferredembodiment of the invention.

In the drawing:

FIGURE 1 is a side elevation of my scaffolding in an extended condition,

FIGURE 2 is an end view of the scaffolding as shown in FIGURE 1,

FIGURE 3 is a fragmentary view showing portions of the scaffolding ofFIGURE 1 in a collapsed condition, and,

3,373,844 Patented Mar. 19, 1968 "ice FIGURE 4 is a fragmentary viewshowing a detail of the assembly.

Reference is now made to the accompanying drawing for a more detaileddescription of the invention and wherein the numeral designatesgenerally a supporting frame or base having casters 11 by which the basemay be moved from one point to another. At one end of the v base 10,there are two laterally spaced pivot forming bearings 12 and at theother extreme end the base 10 there are longitudinally extending guiderails 13 for rollers 14 carried by each of the two laterally spaced lazytong assemblies. The lazy tong assemblies as here shown in FIGURE 1consist of a lower pair of crossed bars 15 and 16 mounted upon tie rods17 at their crossing points.

The cross bars 16 are pivotally mounted at their lower ends upon thepivotal bearings 12 and the cross bars 15 carry the rollers 14 at theirlower ends which ride upon the rails 13. Superimposed upon the crossedbars 15 and '16, there is an additional set of crossed bars 18 and 19that are likewise pivotally mounted upon an additional transverse tierod 17. The cross bar 18 is pivotally connected at its lower end to theupper end of the cross bar 16 of the lower assembly and the lower end ofthe cross bar 19 is similarly pivotally connected to the upper end ofthe cross bar 15. Similar crossed bars 20 and 21 that are pivotallymounted upon the transversely extending tie rods 17 are pivotallyconnected at their lower ends respectively to the upper ends of thecrossed bars 18 and 19, there being in this showing three sets ofcrossed bars, which, when connected as above, will form lazy tongassemblies extending vertically in spaced parallel relation above thesides of the supporting base '10. At its upper end the cross bar 21carries a pivotal mounting for a longitudinally extending platformsupporting member 22 and the upper end of the cross bar 20 carries aroller assembly 23 over which the platform supporting member 22 willfreely ride as the lazy tong arrangement is extended and retracted. Thisarrangement is such that the platform supporting member 22 with aplanking 24 thereupon will retain a substantially level dispositionirrespective of the extension of the lazy tong assemblies. At this pointit should be understood that while there are shown only three sets ofcrossed bars, it is conceivable that any number of similar crossed barsmay be added to provide for a greater elevation of the platform 22 withits planking 24. As a means for extending the lazy tong arrangementconstructed as above described, the base 10 carries a cable retractingdrum 25 from which a cable 26, shown for the sake of clearness in FIGURElof the drawings by dot and dash lines, is payed out and retrieved. Whenthe lazy tong assembly is extended the cable 26 will pass around apulley 27 at the lower end of the crossed bar 15 about a pulley 28 atthe meeting point of the crossed bars 15 and 19, around a similar pulley29 at the pivotal point between the crossed bars 16 and 18 and from thepulley 29 the cable passes from the pulley 29 to a pulley 30 and througha horizontal course to a pulley 31 at the meeting ends of the crossedbars 19 and 21. From the pulley 31, the cable passes around a finalpulley 32 and to a fixed point 33 at the upper end of the crossed bar20. With this arrangement, it will be understood that when the cable 26is retracted by the cable retracting drum 25 a lazy tong extending forcewill be applied directly at the lower end of the crossed bar 15 andsimultaneously in a horizontal direction between the pulleys 28 and 29and the pulleys 30 and 31 as shown by dot and dash lines. The final lazytong extending force will then be exerted between the pulley 32 and thefixed point 33 at the upper end of the crossed bar 20. With the cableaccommodating pulleys 28 to 31 disposed between the connected ends ofthe crossed bars 15 to 21, it will be understood that the cable 3 26will find a free path for movement between these crossed bars to 21, itwill be understood that the cable interrupted dot and dash line betweenthese points. The cable retracting drum is also shown as powered througha chain and sprocket drive 34 by an electric motor 35 under the controlof a switch 36.

As is more clearly shown in FIGURE 2 of the drawings, the parallel linkassemblies above described are held in. spaced and stabilized relationby the tie rods 17 and are also further stabilized by two lazy tongassemblies 37 and 38, each of which consists of three sets of crossedlinks connected in lazy tong fashion, each of which are secured at theirextreme ends and one side at fixed points 39 upon the transverse rods 17so that these lazy tong assemblies will be held in fixed relation at oneend of the stabilizing rods 17. At their other sides and extreme endsthese lazy tong assemblies 37 and 38 are connected to collars 40 thatare slidably mounted upon each of the transverse rods 17. With thisarrangement, it will be seen that as the major lazy tong assembliesconsisting of the crossed links 15 to 21 are extended and collapsedthese latter lazy tong assemblies 37 and 38 will likewise becomeextended and collapsed and at the same time they will exert a furtherstabilizing force between the major lazy tong assemblies. As indicatedin the drawing, the innermost links 15, 18 and 21 of the major lazy tongassemblies are reinforced by transverse braces 41, which, for clarity,have been shown in FIGURE 2 as broken away to more clearly expose theinner lazy tong assemblies 37 and 38.

In FIGURE 1 of the drawing, it will be noted that the lazy tongretracting cable 26, instead of passing directly from the cableretracting drum 25 to the pulley 27 carried by the arm 15, is here shownas passing upwardly and over a pulley 44 that is supported in anelevate-d po- 3 sition and in coplanar relation with a pulley 42 at thepivotal point between the lazy tong bars 15 and 16. The purpose of thiselevated pulley 44 is to provide for an initial upward lifting force atthe pulley 42. This feature becomes operative when, as here indicated bylighter dot and dash lines 26', the pulley 42 is in its lowermost position. To carry out this feature in a more extreme manner, FIGURE 3 showsthe base 10 as having a more extended bracket 45 with a pulley 46 whichwill correspond with the pulley 44 of the FIGURE 1. Therefore, as hereshown by heavy dot and dash lines, an initial retraction of the cable 26upon the drum 15 will exert an upward lifting force upon the pulley 42carried by the crossed bars 15 and 16.

In order to provide for additional leverage in the retraction of thelazy tong extending cable 26, I have in FIGURE 4 of the drawings shownthe cable recoiling drum 25 as in the form of a bobbin with narrowlyspaced sides so that the cable 26 will be wound thereupon in overlappingconcentric turns. In this manner, when the lazy tong assembly iscompletely collapsed the cable 26 will be completely payed out from thedrum so that upon an initial extension of the lazy tong assembly thefirst turn of the cable 26 will be closely adjacent to the axis of thedrum 25 where the maximum cable retracting force will be required.

With the above description, it is believed that the operation of myinvention will be clearly understood, and

while I have, forthe sake of clearness and in order to disclose myinvention so that the same can be readily understood, described andillustrated a specific form and arrangement, I desire to have itunderstood that this invention is not limited to the specific formdisclosed, but may be embodied in other ways that will suggestthemselves to persons skilled in the art. It is believed that thisinvention is new and all such changes as come within the scope of theappended claim are to be considered as part of this invention.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

1. In a scaffolding embodying an extendable lazy tong supportingstructure, the combination of a supporting base having two spacedlongitudinally extending side members, each having a guide rail at oneend and pivotal lazy tong supporting bearings at their other ends, afirst pair of spaced lazy tong elements having one of the crossed barsthereof pivotally mounted upon said pivotal bearing and thecorresponding end of the other of each of said crossed bars havingrollers engaging said guide rails, a second set of crossed barspivotally secured at their lower ends to the upper ends of said firstcrossed bar assembly, an additional set of similarly crossed barsforming an extension of said lazy tong assembly, a horizontallyextending platform member pivotally secured at one end between the crossbars of said last crossed bar, a platform supporting roller between theupper ends of the other of said crossed bars, means for attaching theouter end of a length of cable to said last crossed bars at this point,cable supporting pulleys at the points of con nection between the endsof said cross bars, a cable retracting drum mounted upon said supportingbase, a cable extending from its point of connection to the uppermostbars of said lazy tong assembly passing over and around the pulleys atthe meeting ends of said crossed bars adapted and arranged to exert alazy tong extending force between the successive sets of crossed lazytong forming bars when retracted by said cable retracting drum,characterized by the fact that the crossed bars of each of the lazy tongelements are spaced laterally by a transversely extending tie rod, saidtie rod forming a support for lazy tong assemblies operating in a planeat right angles to said pairs of spaced lazy tong forming elements, theextreme ends of said latter lazy tong assemblies being secured at oneside to a fixed point upon said transversely extending stabilizing rodsand connected at their other extreme ends to collars slidably mountedupon said transversely extending rods, whereby said latter lazy tongassemblies will further operate to stabilize the spaced and parallelrelationship between said first and subsequent pairs of spaced lazy tongelements.

References Cited UNITED STATES PATENTS 559,098 4/1896 Davies --3191,824,673 9/1931 Lee 160319 3,259,369 7/1966 Gridley 182141 FOREIGNPATENTS 124,211 10/1901 Germany.

REINALDO P. MACHADO, Primary Examiner.

